The present invention is directed toward a gauge-based instrument for use in a motor vehicle, and more specifically, toward a gauge-based instrument having a transparent display.
Motor vehicles are generally equipped with a variety of instruments for providing information on the status of the vehicle. These instruments often include a speedometer for indicating the speed of the vehicle, a tachometer for showing the speed of the engine, and various other gauges for showing engine temperature and fluid levels, for example. Similar instrumentation is present on aircraft, boats, motorcycles and other vehicles. These instruments often include analogue gauges wherein a needle or pointer is mounted on the rotary output shaft of a gauge motor and assumes different positions based on the control signal received by the gauge. The needle is positioned near a display bearing markings relevant to the condition being measured, and the needle points to various marks as it turns. For example, if the gauge is part of a speedometer, the markings on the display will indicate various rates of speed in miles or kilometers per hour. Sensors measure the rate of speed of the vehicle and send signals proportional to that speed to the gauge causing the needle to point to the appropriate marking on the display.
Instrumentation must be visible to a person operating a vehicle, and many of the instruments must be read while the vehicle is in motion. A driver will generally focus on the road in front of him when driving, and thus the most convenient location for placing instrumentation has been directly below the driver""s gaze, on the dashboard of the vehicle. The steering wheel is located between the driver and the instrumentation, and partially obstructs the driver""s view of the dashboard. Furthermore, the most important instruments must be large enough for the driver to read and interpret quickly. A vehicle traveling at 60 miles per hour moves 88 feet per second. Thus a driver takes his eyes off the road for 88 feet every time he looks at an instrument for one second. If the instrumentation is small or cannot be read quickly, an even greater time will elapse. In addition, a person""s eyes take a certain amount of time to adjust when shifting focus from a distant point to a proximate point, and a similar time elapses when attention is returned to the distant point. Changes in lighting between the interior and exterior of the vehicle can also make it difficult to switch focus between the road and the dashboard. A driver moving along a highway, for example, generally focuses on the vehicle in front of him or some other point many feet in front of his car. The instruments on a dashboard, meanwhile, are located perhaps one to two feet from the driver""s eyes. The constant shifting of attention from the road to the instruments and the refocusing of eyes involved in this process can be distracting and had the potential to contribute to the occurrence of accidents.
One attempt to overcome this problem was the introduction of so-called xe2x80x9cheads-upxe2x80x9d displays. These displays use complex optics and controls to project an image of an instrument in front of the driver so that the instrument appears to hover in space somewhere over the hood of the vehicle. Similar technology is used in military aircraft. The price of such displays remains high, and therefore this feature is not generally available in average automobiles.
It would therefore be desirable to provide instrumentation that could be read by the driver of a vehicle in a minimal amount of time and with a minimal amount of distraction from driving, that was at the same time easy to use and install and more economical than typical xe2x80x9cheads-upxe2x80x9d displays.
These and other problems are addressed by the present invention which comprises a vehicle instrument with a transparent portion that can be placed in or near a driver""s line of sight without interfering with his view, to allow the instrument to be read with a minimal amount of eye movement and with minimal distraction from the road. Because the instrument can be read without substantially lowering one""s eyes, it may be referred to herein as an xe2x80x9ceyes upxe2x80x9d instrument or display. For simplicity, the subject invention will be described in terms of an instrument for use in an automobile; however, it could as easily be used in a truck, motorcycle, boat, airplane, or any other vehicle that includes instrumentation located generally in front of the driver. In a preferred embodiment, the subject invention comprises a gauge mounted in a clear display with translucent or partially opaque markings and a pointer connected to the gauge for pointing to the markings on the display in a well-known manner. Significantly, such a display can be mounted on the dashboard of a vehicle in a location that would normally interfere with a driver""s view, but because the display is transparent, the driver can readily look through the instrument or ignore it until such time as it become necessary to take another reading. In this manner, the benefits of a heads-up display are obtained at a fraction of the cost. In a second embodiment, the same general instrument design is used, but the display is enclosed within a housing so that a driver cannot look through the instrument to the road beyond. However, due to the compact size of the display produced in accordance with this invention, and the method of illuminating the display from one edge and/or from beneath, low profile gauges can be provided for mounting on a dashboard so as not to interfere with a driver""s vision. These low profile gauges may be located closer to the driver""s line of sight than instruments mounted in a dashboard in a traditional manner and thus provide many of the advantages of the first embodiment of the invention. In accordance with another aspect of the invention, thin screens are molded into the display or attached to the front or rear of the display in order to control the angle at which light leaves the display to minimize unwanted reflection off the windshield.
It is therefore a principal object of the present invention to provide improved instrumentation for vehicles.
It is another object of the invention to provide instrumentation that can be viewed by the driver of a vehicle with minimal eye movement.
It is a further object of the invention to provide transparent instrumentation that can be placed in or near the line of sight of a driver.
It is still another object of the invention to provide instrumentation mounted at or above the dashboard level in a vehicle.
It is still a further object of the invention to provide illuminated instrumentation having a transparent display.
It is yet another object of the invention to provide an instrumentation cluster of the foregoing character.
It is yet a further object of the invention to provide instrumentation having a display that can be readily configured with a variety of different markings.